The new action inheritdsfield copies the field DS of IPv4 and IPv6 packets into skb->priority. This enables later classification of packets based on the DS field.
v2: *Use optional flags, so that it won't break old versions of tc. Original idea by Jamal Hadi Salim <j...@mojatatu.com> Signed-off-by: Qiaobin Fu <qiaob...@bu.edu> Reviewed-by: Michel Machado <mic...@digirati.com.br> --- Note that the motivation for this patch is found in the following discussion: https://www.spinics.net/lists/netdev/msg501061.html --- diff --git a/include/uapi/linux/tc_act/tc_skbedit.h b/include/uapi/linux/tc_act/tc_skbedit.h index fbcfe27a..6de6071e 100644 --- a/include/uapi/linux/tc_act/tc_skbedit.h +++ b/include/uapi/linux/tc_act/tc_skbedit.h @@ -30,6 +30,7 @@ #define SKBEDIT_F_MARK 0x4 #define SKBEDIT_F_PTYPE 0x8 #define SKBEDIT_F_MASK 0x10 +#define SKBEDIT_F_INHERITDSFIELD 0x20 struct tc_skbedit { tc_gen; @@ -45,6 +46,7 @@ enum { TCA_SKBEDIT_PAD, TCA_SKBEDIT_PTYPE, TCA_SKBEDIT_MASK, + TCA_SKBEDIT_FLAGS, __TCA_SKBEDIT_MAX }; #define TCA_SKBEDIT_MAX (__TCA_SKBEDIT_MAX - 1) diff --git a/tc/m_skbedit.c b/tc/m_skbedit.c index db5c64ca..b7f27f09 100644 --- a/tc/m_skbedit.c +++ b/tc/m_skbedit.c @@ -30,16 +30,18 @@ static void explain(void) { - fprintf(stderr, "Usage: ... skbedit <[QM] [PM] [MM] [PT]>\n" + fprintf(stderr, "Usage: ... skbedit <[QM] [PM] [MM] [PT] [IF]>\n" "QM = queue_mapping QUEUE_MAPPING\n" "PM = priority PRIORITY\n" "MM = mark MARK\n" "PT = ptype PACKETYPE\n" + "IF = inheritdsfield\n" "PACKETYPE = is one of:\n" " host, otherhost, broadcast, multicast\n" "QUEUE_MAPPING = device transmit queue to use\n" "PRIORITY = classID to assign to priority field\n" - "MARK = firewall mark to set\n"); + "MARK = firewall mark to set\n" + "note: inheritdsfield maps DS field to skb->priority\n"); } static void @@ -60,6 +62,7 @@ parse_skbedit(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, unsigned int tmp; __u16 queue_mapping, ptype; __u32 flags = 0, priority, mark; + __u64 pure_flags = 0; struct tc_skbedit sel = { 0 }; if (matches(*argv, "skbedit") != 0) @@ -111,6 +114,9 @@ parse_skbedit(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, } flags |= SKBEDIT_F_PTYPE; ok++; + } else if (matches(*argv, "inheritdsfield") == 0) { + pure_flags |= SKBEDIT_F_INHERITDSFIELD; + ok++; } else if (matches(*argv, "help") == 0) { usage(); } else { @@ -156,6 +162,9 @@ parse_skbedit(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, if (flags & SKBEDIT_F_PTYPE) addattr_l(n, MAX_MSG, TCA_SKBEDIT_PTYPE, &ptype, sizeof(ptype)); + if (pure_flags != 0) + addattr_l(n, MAX_MSG, TCA_SKBEDIT_FLAGS, + &pure_flags, sizeof(pure_flags)); addattr_nest_end(n, tail); *argc_p = argc; @@ -171,6 +180,7 @@ static int print_skbedit(struct action_util *au, FILE *f, struct rtattr *arg) __u32 *priority; __u32 *mark; __u16 *queue_mapping, *ptype; + __u64 *flags; struct tc_skbedit *p = NULL; if (arg == NULL) @@ -211,6 +221,11 @@ static int print_skbedit(struct action_util *au, FILE *f, struct rtattr *arg) else fprintf(f, " ptype %d", *ptype); } + if (tb[TCA_SKBEDIT_FLAGS] != NULL) { + flags = RTA_DATA(tb[TCA_SKBEDIT_FLAGS]); + if (*flags & SKBEDIT_F_INHERITDSFIELD) + fprintf(f, "inherit DS field "); + } print_action_control(f, " ", p->action, "");
